1. Field of the Invention
The present invention relates to a substrate processing method and a method for manufacturing a liquid ejection head such as an ink jet recording head.
2. Description of the Related Art
A conventional method for manufacturing an ink jet recording head has the following steps as is disclosed in U.S. Pat. No. 6,534,247: a step of forming a layer having an ink-ejecting energy generating element on the upper portion of a silicon substrate and then digging a part of the above described layer so as to reach the above described substrate, a step of forming a nozzle part on the upper portion of the above described layer, a step of wet-etching the above described substrate to form a common ink-supply port, a step of applying a resist in the common ink-supply port, a step of patterning the bottom face portion of the common ink-supply port, and a step of forming an independent supply port by dry-etching the above described substrate so that the independent supply port communicates with the dug part in the above described layer.